Representatives of the investment banking and securities industries said yesterday they generally agree on the need to tighten federal laws governing takeover attempts, but both said a proposed Senate bill goes too far.

Testifying before the Senate Banking Committee, John W. Bachmann, chairman of the Securities Industry Association, and Robert F. Greenhill, managing director of Morgan Stanley & Co., said legislation promoted by the committee's chairman may tilt the contests against corporate raiders.

"We favor a balanced package of reforms" that will curb abuses by both raiders and defensive managers, said Greenhill, who also testified for First Boston Corp. and Goldman, Sachs & Co. "The tactics of both sides are undermining investor confidence in the integrity of corporate control contest{s}."

Bachmann said the bill contains many elements also proposed by an SIA task force earlier this year. But it also contains "troublesome" items that could unnecessarily burden corporate raiders.

The bill, sponsored by Sen. William Proxmire (D-Wis.), would require corporate raiders to publicly disclose their holdings and intentions within a day of acquiring 3 percent of a company. Under current law, they have 10 days after acquiring 5 percent, and critics say that tips the playing field toward the raider.

Bachmann said the SIA agrees the 10-day "window" should be closed and said the one-day requirement proposed by Proxmire is not too different from that proposed by the association.

However, he said the association opposes lowering the disclosure threshold from 5 percent to 3 percent because the lower figure "will result in many additional meaningless reports being filed with the SEC without any compensating regulatory benefit or benefit to shareholders."

Bachmann said the association also opposes Proxmire's requirement that tender offers remain open for a minimum 35 business days, or seven calendar weeks.

"The longer the period that a tender offer is open, the more costly the financing for the offeror," he said. "This, of course, tips the scales in favor of incumbent managment."

The SIA has proposed that tender offers remain open for a minimum of 30 calendar days.

Greenhill expressed similar views. The opinions of the two groups were so similar, in fact, that Proxmire asked if their testimony had been prepared in concert. Both men said their testimony had been prepared independently.

But in differing views, the 13 million-member AFL-CIO said Proxmire's bill was too modest in preventing takeover abuses.

Laurence Gold, general counsel for the labor federation, said the bill would "go a long way toward creating a system that is fairer for stockholders and investors."